Mass polymerization process in the presence of polyalkylene glycols



United States Patent "ice 3,385,912 MASS POLYMERIZATEUN PROQESS IN THEPRESENCE OF PULYALKYLEN E GLYCQLS Alva l Fli'arris, Wilhraham, Mass,assignor to Monsanto Company, St. Louis, Mo, a corporation of DelawareNo Drawing. Filed Nov. 12, 1905, ar. No. 507,575 13 Claims. (Cl.260-4380) ABSTRACT OF THE DlSCLflSURE There is disclosed a masspolymerization process for monovinylidene aromatic hydrocarbons whereinthere is incorporated in the polymerizable mixture a polyalkyleneglycol, following which the mixture is heated to produce polymerizationof the monomers. Thereafter the polymerized formulation is separatedfrom the reaction vessel.

The present invention relates to a novel process for the masspolymerization of styrene-type monomers.

It is well known that stryene-type monomers can be mass polymerizedthermally or catalytically to prepare polymers having molecular weightsand residual monomer contents which vary with certain reactionparameters; e.g., the catalyst concentration, the time and temperatureof the reaction, etc. It is also known that the product of the masspolymerization process may have an undesirably high residual monomercontent when the parameters of the process are controlled so as toprepare a moldinggrade polystyrene; i.e., a polystyrene having aStaudinger average molecular weight in the range of 40,000 to 100,000.

As shown in the United States Patent No. 2,675,362, certain catalystsmake it possible to use a mass polymerization process to preparemolding-grade polystyrene having a residual monomer content as low as0.35 to 0.5 percent and the product has improved physical and moldingproperties because of the reduction in residual monomer content.Accordingly, it has been considered desirable to find and employ acatalyst capable of reducing the residual monomer content to even lowerlevels without otherwise causing degradation of the product because ofthe advantages which might be obtained thereby. Accordingly, it has beensuggested to employ a catalyst system containing an organoperoxysilanein United States application for Letters Patent Ser. No. 385,061, filedJuly 24, 1964, and entitled, Polymerization Process, granted on Jan. 10,1967 as United States Patent No. 3,297,669.

In one type of mass polymerization process, the monomers are initiallypolymerized in a kettle or reaction vessel over a relatively lowtemperature range on the order of 125 to 75 centigrade to a conversionon the order of about 15.0 to 45.0 percent. Thereafter, the partiallypolymerized mass is transferred to a platen and frame-type press whereinthe temperature thereof is gradually raised to about 180 to 200centigrade over a period of three to seven hours, and is finally heatedat about 180 to 200 centigrade for about one to five hours to completethe reaction. After polymerization has been completed, the polymer iscooled to about 30 to 70 centigrade, and the platens are removed and thecakes of polymer extracted from the frames. Exemplary of such pressesare those disclosed in United States Patent No. 2,067,580, granted Jan.12, 1937 to Otto Rohm; and United States Patent No. 3,140,917, grantedJuly 14, 1964, to Max Klein.

It is an object of the present invention to provide a novel process formass polymerizing styrene-type monomers wherein a platen and frame-typepress is utilized and wherein separation of the polymerized mass from3,385,912 Patented May 28, 1968 the platen and frames of the press isfacilitated and maintainance of the press is reduced.

Another object is to provide a novel mass polymerization processutilizing an organoperoxysilane catalyst to provide a polymer with lowresidual monomer content.

Other objects and advantages will be readily apparent from the followingdetailed specification. and claims.

It has now been found that the foregoing and related objects can bereadily attained in a process wherein a monovinylidene aromatic monomerselected from the group consisting of a monovinylidene aromatichydrocarbon and ar-halo monovinylidene aromatic hydrocarbon and mixturesthereof is admixed with 0.05 to 1.0 percent by weight, based upon thetotal weight of the admixture, of a polyalkylene glycol, and the monomeris thereafter polymerized, in mass, by heat and a catalyst. Inaccordance with one aspect of the process, the admixture is initiallypartially polymerized at a temperature of about to 125 centigrade toeffect conversion of about 15.0 to 45.0 percent of the monomer. Thisinitially partially polymerized admixture is then transferred to aplaten and frame-type press wherein it is subjected to increasingtemperature and gradually raised to about 180 to 200 centigrade, afterwhich it is maintained at a temperature of about 180 to 200 centigradeto effect substantially complete conversion of the monomer. Thepolymerization product is then cooled to a temperature of 20 to 70centigrade while in the press, and the press is then opened. The platensare removed, and the cakes of polymerization product are extracted fromthe individual frames of the press.

In accordance with the preferred aspect of the present invention thecatalyst employed is an organoperoxysilane having a half life of about220 to 30,000 hours in benzene at centigrade, and the admixture isinitially heated at 75 to centigrade until 15.0 to 45.0 percentconversion to polymer is obtained. the temperature being so regulated asto be in the 75 to 95 centigrade range when this conversion is obtained.Thereafter, the reaction temperature of the admixture is graduallyraised to to 200 centigrade over a period of about three to seven hoursand maintained at 180 to 200 centigrade for about one-half to five hoursto effect substantially complete conversion of the monomer.

The polyalkylene glycol The polyalkylene glycols have a structuralformula wherein R and R" are hydrogen or methyl groups but only one ofwhich may be a methyl group in any given polyalkylene glycol so astogether to provide not more than one carbon atom, and n is selected toproduce an average molecular weight of 800 to 4500.

As is well known in the art, such compounds are produced by condensingan alkylene oxide or mixtures of alkylene oxides. The preferredcompositions are polyethylene glycols, although mixed condensates ofethylene oxide and propylene oxide may be highly advantageous. Exemplaryof such compositions are polyethylene glycols, polypropylene glycols,and poly(ethylene oxypropylene oxy) glycols. As the average molecularweight falls below 1000, the suitability of the glycol decreases and asthe average molecular weight is increased above 4000, the solubility instyrene rapidly decreases. The preferred agent is polyethylene glycolhaving an average molecular weight of about 1000-2000.

Although this component may be added in the amount of 0.05 to 1.0percent by weight of the monomer admixture with beneficial effect, it ispreferably employed in the range of 0.1 to 0.4 percent by weight due toconsiderations of optimum GfllCiQHCY, ease of handling and economics.Generally, the component is readily admixed directly with the monomer,although it may be added as a solution or dispersion in anothercomponent if so desired to minimize separate additions.

Monomers The present invention is applicable to the polymerization ofpolymerizable monomers comprising a monovinylidene aromatic hydrocarbonand/ or an ar-halo monovinyiidene aromatic hydrocarbon, e.g., styrene;vinyl napthalene; ar-alkylstrenes, such as o-, mand p-methylstyrenes,ar-ethylstyrenes, p-tert-butylstyrene; etc.; arhalostyrenes, such aso-chlorostyrene, p-bromostyrene, 2- chloro-4-methylstyrene, etc.; andmixtures thereof. The monovinylidene aromatic monomer may constitute theonly component of the polymerizable material or may be in admixture withone or more copolymerizable monomers, such as acrylonitrile;methacrylonitrile; an alkyl methacrylate, e.g., the methyl, ethyl,propyl, and butyl methacrylates; the corresponding alkyl acrylates;alpha-alkylstyrenes, e.g., alpha-methylstyrene, alpha-ethylstyrene,alpha-methyl-p-methylstyrene, etc. Ordinarily, the monovinyl aromaticmonomer constitutes at least 50.0 percent by Weight of the polymerizablematerial.

When desired the polymerizable material can have a rubbery conjugated,1,3-diene polymer (e.g., natural rub- 23 ber, polybutadiene,polyisoprene, copolymers of butadiene and/ or isoprene with lesseramounts of cornonomers such as styrene, acrylonitrile, methylmethacrylate, etc.) dissolved therein, ordinarily in concentrations of1.0 to 25.0 percent, based on the weight of polymerizable material.Also, the reaction mixture can contain other optional ingredients, e.g.,plasticizers and stabilizers, etc. To minimize possible deleteriouseffect upon certain catalysts and particularly the preferredorganoperoxysilane catalysts, the monomers employed should besubstantially free from moisture and are desirably dried.

Catalysts The present invention is applicable to various types ofcatalyst systems useful in polymerizing the monomers such as theconventional monomer-soluble peroxy compounds having a half life of to15,000 hours in benzene at 100 Centigrade. Utilizable peroxy compoundsinclude, e.g., hydrogen peroxide, di-tert-butyl diperphthalate,tert-butyl peracetate, tert-butyl perbenzoate, dicumyl peroxide,di-tert-butyl peroxide, tert-butylperoxyisopropyl carbonate, 2,5dimethyl 2,5 di(tert butylperoxy) hexane, 2,5dimethyl-2,5,-di(tert-butylperoxy)hexyne-3, tert-butyl hydroperoxide,cumene hydroperoxide, pmenthane hydroperoxide, cyclopentanehydroperoxide, diisopropylbenzene hydroperoxide, p-tert-butylcumenehydroperoxide, pinane hydroperoxide, 2,5-dihydroperoxide, etc., andmixtures thereof.

However, the preferred catalyst systems of the present invention arethose utilizing an organoperoxysilane to provide high temperaturecatalytic activity so as to reduce the residual monomer content to arelatively low level. The organoperoxysilanes can be any monomer-soluble'organoperoxysilane having a half life of about 220 to 30,000 hours inbenzene at 100 ccntigrade, but the organo peroxysilanes having halflives in benzene of about 500 to 30,000 hours, particularly 8,000 to28,000 hours, are preferred. Organoperoxysilanes having half livessubstantially shorter than about 220 hours in benzene at 100 centigradeare not advantageous in the practice of the invention because they arecompletely or substantially completely consumed before the reactionreaches the finishing stage, i.e., the stage conducted at 180 to 200centigrade, then the presence of a catalyst is required in order toreduce residual monomer content. Organo- 4 peroxysilanes having halflives longer than about 30,000 hours in benzene at centigrade are atleast less efficient and are completely ineffective when they are toostable to decompose at temperatures of to 200 centigrade.

Although trimethylsilylperoxytrimethylsilane and otherorganoperoxysilanes containing more than one silicon atom and havingsuitable half lives can be employed, the preferred organoperoxysilanesare compounds corresponding to the formula:

wherein R R and R are independently selected from the group consistingof alkyl, cycloakyl, aryl and aralkyl radicals and R R and R areindependently selected from the group consisting of alkyl, cycloakyl,aryl and aralkyl radicals and a radical corresponding to the formula:

wherein R R and R are independently selected from the group consistingof alkyl, cycloakyl, aryl and aralkyl radicals. Exemplary of the alkyl,cycloakyl, aryl and an alkyl radicals which can be present in thesecompounds are methyl, ethyl, propyl, butyl, pentyl, hexyl, cyclobutyl,cyclopentyl, cyclohcxyl, menthyl, phenyl, totyl, naphthyl, benzyl, etc.The preferred compounds are those in which the alkyl and cycloaikylradicals contain up to 6 carbon atoms and the aryl and aralltyl radicalscontain up to 12 carbon atoms.

Such compounds, when not commercially available, can be prepared byreacting a suitable halosilane (e.g., diethyldifluorosilane,ethyltrifluorosilane, tetratluorosilane, trimethylchlorosilane,triphenylchlorosilane, ditolyldichlorosilane, naphthyltriiiuorosilane,dicyclohexyldichlorosilane, benzyltrichlorosilane,ethylisohutylbenzylchlorosilane, etc.) with a suitable organichydroperoxide or mixture of organic hydroperoxides in the presence of ahydrogen halide acceptor such as ammonia or an amine in a solvent suchas ether, etc., essentially in accordance with the equation:

wherein X represents a halogen, (i.e. F, Cl, Br, or I), R and Rrepresent alkyl, cycloalkyl, aryl, or aralkyl radicals, and n is aninteger of 1 to 4.

Exemplary of the organoperoxysilanes which can be employed aretert-butylperoxytrimethylsilane,

di (tert-butylperoxy) dimethylsilane,

tri tert-butylp eroxy) methylsilane,

tetra (tert-butylperoxy) silane,

di (tert-butylperoxy methyl phenylsilane, di tertbutylperoxy)diphenylsil ane,

tri (tert-butylperoxy phenylsilane, tert-butylperoxytriethylsilane,

di (tert-butylperoxy) diethylsilane,

tri tert-butylperoxy) benzylsilane,

tri( tert-butylperoxy naphthylsilane,

tri (tert-butylperoxy) cyclohexylsilane,tert-arnylperoxytrimethylsilane, 2-phenyl-2-propylperoxytrimethylsilane,p-menthylperoxytrimethylsilane,

etc., and mixtures thereof.

The amount of organoperoxysilane employed varies with the particularproduct desired but is ordinarily in the range of about 0.001 to 0.1percent, based on the weight of the polymerizable material. The lowerconcentrations of silane, e.g., about 0.001 to 0.04 percent, are usuallyemployed when a co-catalyst is used; the higher concentrations ofsilane, e.g., about 0.04 to 0.1

percent are usually employed when no co-catalyst is used.

In many instances, it is desirable to employ the organoperoxysilane incombination with a conventional peroxy catalyst because of the catalyticeffectiveness of such peroxy compounds at the temperatures employedprior to the finishing stage of the reaction, i.e., at temperatures of75 to 180 centigrade. When included as a catalyst component, in such acombined catalyst system, the peroxy compound is usually employed inconcentrations of 0.01 to 0.1 percent by weight of the monomer, andpreferably about 0.01 to 0.05 percent by weight.

Polymerization process The monomers are initially polymerized in akettle or reaction vessel over a relatively low temperature range on theorder of 125 to 75 centigrade to obtain conversion of the monomer to theextent of about to 45 percent. Thereafter, the partially polymerizedmass is heated so as to gradually raise the temperature thereof to about180 to 200 centigrade over a period of three to seven hours, after whichit is finally heated at a. temperature of about 180 to 200 centigradefor about one to five hours to complete the polymerization reaction.

In accordance with the preferred aspect of the present invention, thepartially polymerized mass is transferred to a platen and frame-typepress where the temperature is elevated and the final polymerizationconducted. After the polymerization has been completed, coolant is supplied to the press to cool the polymer to a temperature of about 30 to70 centigrade, the platens are removed and the cakes of polymerextracted from the frames.

When using a catalyst composition according to the preferred processwherein organoperoxysilanes are included, a fairly specifictime-temperature cycle is utilized. In the first stage of the reaction,polymerization is conducted at 75 to 125 centigrade for about six totwentyfour hours until 15.0 to 45.0 percent of the monomer has beenconverted to polymer; in the second stage, the reaction temperature isgradually raised from 75 to 95 centigrade to 180 to 200 centigrade overa period of about three to seven hours; in the final stage, the reactiontemperature is maintained at 180 to 200 centigrade for about one-half tofive hours.

The manner of manipulating the reaction temperature during the firststage of the reaction in order to be in the 75 to 95 centigrade rangefor the beginning of the second stage of the reaction is not critical,e.g., an initial temperature of about 100 to 125 centigrade can begradually lowered to 75 to 95 centigrade during the first stage of thereaction or the temperature can be main tained at 75 to 95 centigradethroughout the first stage of the reaction, etc. According to apreferred embodiment, the reaction mixture is initially heated to 105 to115 centigrade and the temperature gradually lowered to about 90centigrade until about 25.0 to 45.0 percent conversion to polymer isobtained, after which the temperature is gradually raised to 180 to 200centigrade over a period of about three to seven hours and thenmaintained at 180 to 200 centigrade for about one to five hours tocomplete the reaction. Especially good results are also obtained byinitially heating the reaction mixture at 90 centigrade to about 25 to35 percent conversion, then heating at a temperature gradually raised to180 to 200 centigrade over a period of about four to five hours, andfinally heating at 180 to 200 centigrade for one to four hours.

The polymer cakes produced by the present invention are found to releasereadily from the frames of the press and to subsequently exhibitself-lubricating properties in molding operations. The polymer cakes areglossy and free from haze and color. In addition to providing lowmaintenance upon the polymerization equipment, the more facile operationand utilization of this type polymerization process enhances theeconomics thereof.

Illustrative of the efiicacy of the present invention are the followingspecific examples in which all parts are parts by weight.

EXAMPLE 1 Part A-Control In 100 parts of styrene were dissolved 0.04part of ditert-butyl peroxide and 0.01 part dimethyl di-(tert-butylperoxy) silane. The reaction vessel was purged with nitrogen and heatedby a fluid at a temperature of about to centigrade for about twentyhours to convert about 30.0 percent of the styrene to polymer. Thepartially polymerized mass was then gradually raised in temperature by aheating fluid which has its temperature increased from about 90centigrade to about 180 centigrade over a period of about six andone-half hours in a platen and frame type press. Thereafter, the heatingfluid was held at about 180 centigrade for two hours to completepolymerization. The press was then cooled to about 30 centigrade andopened. The platens were separated from the cakes of polymer and thecakes extracted from the frames.

It was noted that the cakes adhered to the platens and to the framesmaking separation difiicult and also that the platens had a White filmof polymer remaining thereon after separation requiring cleaning ofthese surfaces.

The polymer product had a Staudinger average molecular weight of about65,000 and a residual monomer content of 0.29 percent by weight.

Part B A product was prepared by substantially repeating Part A andincluding in the monomer formulation 0.2 part polyethylene glycol havingan average molecular weight of 1000, sold by Union Carbide and ChemicalCorporation under the designation Carbowax 1000.

It was noted that the polymer cakes produced by this formulationseparated readily from the platens and frames which evidenced noresidual film of polymer thereon. The cakes had glossy surfaces and thepolymer was free from haze and color.

The polymer product had a Staudinger average molecular weight of about69,000 and a residual monomer content of 0.17 percent by Weight, thusevidencing a reduction in residual monomer content.

EXAMPLE 2 Isothermal polymerization tests were conducted utilizingstyrene monomer, 0.04 part di-tert-butyl peroxide catalyst, 0.01 partdimethyl di(tert-butyl peroxy)silane at a temperature of 90 centigradeand at forty-eight hours. To one test sample was added 0.2 part stearicacid and to another test sample was added 0.3 part of polyethyleneglycol having an average molecular weight of 1000.

At the end of the isothermal polymerization, fifty-eight (58) percent ofthe monomer in the control sample was converted to polymer. In the testsample, containing stearic acid, ninety-five (95) percent of the monomerwas converted. In the test sample containing the polyethylene glycol,seventy (70) percent of the monomer was converted.

It can be seen that the stearic acid has a seriously deleterious effectupon the preferred organoperoxysilane catalyst by causing prematureinduced decomposition of this high temperature catalyst, thus reducingits effectiveness at high temperature to complete polymerization andminimize residual monomer. However, the addition of the polyalkyleneglycols of the present invention results in greatly reduced effect uponthe highly desirable organoperoxysilane catalyst.

EXAMPLE 3 In parts of styrene were dissolved 0.04 part ofditert-outylperoxide and 0.3 part of polyethylene glycol having anaverage molecular weight of 1000. A strip of polished stainless steelwas inserted into the reaction vessel with a portion thereof projectingoutwardly, and

the reaction vessel was heated in an oven utilizing a cycle similar tothat of Example 1 wherein the initial heating step utilized was 90centigrade for twenty-four hours, the temperature elevation to 180centigrade being conducted over three and one-half hours, and thetemperature finally being held at 180 Centigrade for four hours. Noorganoperoxysilane catalyst was included. The stainless steel strip wasreadily removed from the polymer and exhibited a bright surface was nopolymer film thereon. The polymer itself was free from haze and color.

The foregoing test tends to simulate results obtained in a platen andframe type press and is somewhat more stringent in some respects in thatthe strip is not cooled by a fluid as in the case of the platens of thepress so that shrinkage may enhance the separation.

EXAMPLE 4 The test of Example 3 was repeated substituting polypropyleneglycol having an average molecular weight of 2025.

After polymerization, the stainless steel strip was removed readily fromthe polymer and exhibited a bright surface with no polymer film thereon.The polymer itself was free from color and haze.

As will be readily appreciated from the foregoing examples and detailedspecification, the present invention provides a novel process for masspolymerizing styrenetype monomers which is particularly advantageouslyemployed in a process wherein a platen and frame type press is utilized.in addition, the process of the present invention is facile andeconomically advantageous for obtaining a low residual monomer contentin the polymer by use of an organoperoxysilane catalyst. Subsequentmolding operations utilizing the polymer produced according to thepresent invention are readily conducted without the necessity for moldlubricants since the polymer itself possesses a satisfactory degree ofmold lubricity.

The reaction mixture can contain other optional ingredients, e.g.,plasticizers, stabilizers, etc., if so desired.

It is obvious that many variations can be made in the A processes setforth without departing from the spirit and scope of this invention.

What is claimed is:

1. A mass polymerization process which comprises (1) forming a reactionmixture by dissolving in a polymerizable material comprising at least 50percent by weight of a monovinylidene aromatic monomer of the groupconsisting of a monovinylidene aromatic hydrocarbon, an ar-halomonovinylidene aromatic hydrocarbon, and mixtures thereof, amonomer-soluble free radical catalyst and 0.05 to 1.0 percent by weight,based upon the weight of the reaction mixture, of a polyalkylene glycolcorresponding to the following formula:

wherein R and R" are hydrogen or methyl groups but only one of which maybe a methyl group in a given polyalkylene glycol so as together toprovide not more than one carbon atom, and n is selected to provide aiolecular weight of 8004500; (2) subjecting said reaction mixture in areaction vessel to a heating cycle sufficient to produce polymerizationthereof and form a polymerization product; and (3) thereafter separatingsaid polymerization product from said reaction vessel.

2. The process of claim 1 wherein the polyalkylene glycol is apolyethylene glycol having an average molecular weight of about1000-2000.

3. The process of claim 1 wherein the catalyst includes anorganoperoxysilane having a half life of about 220 to 30,000 hours inbenzene at 100 centigrade.

4. The process of claim 1 wherein said heating cycle includes initialpolymerization at a temperature of about 75 to 125 centigrade to aconversion on the order of 8 about 15.0 to 45.0 percent, gradualelevation in temperature to about 180 to 200 Centigrade over a period ofthree to seven hours and maintenance at a temperature of about 180 to200 centigrade for about one to five hours to complete thepolymerization reaction.

5. The process of claim 4 wherein said steps of gradual elevation oftemperature to about 180 to 200 centigrade and maintenance at about 180to 200 centigrade are conducted in a platen and frame-type pressproviding the reaction vessel and wherein the press is cooled afterpolymerization has been completed and the platens and frames arethereafter separated from the polymerization product.

6. The process of claim 4 wherein said catalyst includes anorganoperoxysilane having a half life of about 220 to 30,000 hours inbenzene at 100 centigrade.

'7. The process of claim 3 wherein the organoperoxysilane is a compoundcorresponding to the formula:

wherein R R and R are independently selected from the group consistingof alkyl, cycloalkyl, aryl and aralkyl radicals and R R and R areindependently selected from the group consisting of alkyl, cycloalkyl,alyl, and aralkyl radicals and a radical corresponding to the formula:

wherein R R and R are independently selected from the group consistingof alkyl, cycloalkyl, aryl and aralkyl radicals.

8. The process of claim 1 wherein the polymen'zable material is styrene.

9. The process of claim 1 wherein the polymerizable material isstyrene-acrylonitrile.

10. The process of claim 1 wherein the polymerizable material contains adissolved rubbery conjugated 1,3-dione polymer.

ill. A mass polymerization process which comprises (1) forming areaction mixture by dissolving in a polymerizable material comprising atleast 50 percent by weight of a monovinylidene aromatic monomer of thegroup consisting of a monovinylidene aromatic hydrocarbon, an ar-halomonovinylidene aromatic hydrocarbon, and mixtures thereof, amonomer-soluble free radical catalyst including an organoperoxysilanecorresponding to the formula:

R1 R4 R2( )OOS iR5 I l/3 6 wherein R R and R are independently selectedfrom the group consisting of alkyl, cycloalkyl, aryl and aralkylradicals and R R and R are independently selected from the groupconsisting of alkyl, cycloalkyl, aryl and aralkyl radicals and a radicalcorresponding to the formula:

I51 Rs-(I]OO wherein R R and R are independently selected from the groupconsisting of alkyl, cycloalkyl, aryl and aralkyl radicals and 0.05 to1.0 percent by weight, based upon the total weight of the reactionmixture, of a polyalkylene glycol corresponding to the followingformula:

R! R! R! R l l g I lIO (|)-(|3o C-OH H II n H H wherein R and R" arehydrogen or methyl groups but only one of which may be a methyl group ina given polyalkylene glycol so as together to provide not more than onecarbon atom, and n is selected to provide a molecular weight of800-4500; (2) heating the reaction mixture at about 75 to 125 centigradeto effect conversion of about 15.0 to 45.0 percent of the polymerizablematerial; (3) transferring the partially converted reaction mixture to aplaten and frame type press; (4) heating said reaction mixture in theplaten and frame type press with a fluid having a temperature graduallyraised to about 180 to 200 centigrade over a period of about three toseven hours; (5) heating said reaction mixture in the press with a fluidhaving a temperature of about hours to complete the polymerizationreaction and form a polymerization product; (6) cooling the platen andframe press and polymerization product; and (7) thereafter separatingthe platens and frames from said polymerization product.

'12. The process of claim 11 wherein. the polyalkylene glycol ispolyethylene glycol having an average molecular weight of about1000-2000.

13. The process of claim 12 wherein said organoperoxysilane isdi-(tert-butylperoxy)dimethylsiilane.

No references cited.

JOSEPH L. SCHOFER, Primary Examiner.

180 to 200 centigrade for a period of about one to five 15 H. WONG,Assistant Examiner.

